SOLUTION: I have problem 4^-2 +8-6^2(2+1). I got answer of -6.25. Book has -99.9375. What did I do wrong. I thought you had to make exponent positive before you could solve it. Tks

Algebra ->  Exponents-negative-and-fractional -> SOLUTION: I have problem 4^-2 +8-6^2(2+1). I got answer of -6.25. Book has -99.9375. What did I do wrong. I thought you had to make exponent positive before you could solve it. Tks      Log On


   

Question 711645: I have problem 4^-2 +8-6^2(2+1). I got answer of -6.25. Book has -99.9375. What did I do wrong. I thought you had to make exponent positive before you could solve it. Tks
Found 2 solutions by god2012, nerdybill:
Answer by god2012(113) About Me  (Show Source):
You can put this solution on YOUR website!
Given : 4%5E-2+%2B+8+-+6%5E2%282+%2B+1%29+
Solution :
%281%2F4%5E2%29+%2B+8+-+36+%2A3+
%281%2F16%29+%2B+8+-+108
%281%2F16%29-100
%281-1600%29%2F16
-1599%2F16 = -99.9375

Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
Apply the "order of operations" -- (PEMDAS)
4^-2 +8-6^2(2+1)
parentheses first:
4^-2 +8-6^2(3)
exponents next:
1/4^2 +8-6^2(3)
1/16 +8-36(3)
multiplication/division (left to right):
.0625 +8-108
addition/subtraction (left to right):
8.0625-108
-99.9375